1. Field of the Invention
The present invention relates to an electrode for a plasma display panel (PDP) in which an electrode having a high adhesive power is formed on a glass substrate of a color plasma display panel; and a method for forming the same.
2. Discussion of the Related Art
FIG. 1 is a cross-sectional view showing a structure of a conventional PDP.
Referring to FIG. 1, a pair of upper electrodes 4 are formed on a front glass substrate. A dielectric layer 2 is formed over the pair of the upper electrodes 4 by employing a printing method and a protecting layer 3 is formed on the dielectric layer 2 by a deposition method. The pair of upper electrodes 4, and the dielectric layer 2 and the protecting layer 3 constitute an upper structure.
A lower electrode 12 is formed on a back glass substrate 11. Sidewalls 6 are formed in order to prevent crosstalk between adjacent cells. Luminescent materials 8, 9, and 10 are formed on the both sides of each of the sidewalls 6 and on the back glass substrate 11. The lower electrode 12, the sidewalls 6, and the luminescent materials 8, 9, and 10 constitute an lower structure. A non-active gas fills the space between the upper electrodes 4 and the lower electrode 12 such that a discharge region 5 is formed.
The operation of a general PDP will be explained.
Referring to FIG. 1, a driving voltage is applied to the pair of the upper electrodes 4 so that a surface discharge is generated in the discharge region 5, thereby generating ultraviolet 7. The ultraviolet 7 excites the luminescent materials 8, 9, and 10, to achieve a color display. In other words, the space charge which is present in the discharge cell is traveled to cathode due to the driving voltage. The space charge collides with non-active mixed gas which is a penning mixed gas added to by xenon (Xe), and neon (Ne), helium (He) which is the main component of the mixed gas, such that the non-active gas is exited and the ultraviolet 7 of 147 nm is generated. The non-active gas which fills the discharge has a pressure of 400-500 torr.
The ultraviolet 7 generated collides with the luminescent material 8, 9, and 10 on the sidewalls 6 and the back glass substrate 11, thus forming a visible ray region.
FIGS. 2a and 2b are cross-sectional views showing the upper and lower substrates of a PDP according to a conventional method.
As shown in FIG. 2a, for the lower substrate, a metal conductive material 30 such as nickel (Ni) or aluminum (Al) is formed on a back glass substrate 11 (dielectric substrate) by a printing technique. As shown in FIG. 2b, for the upper substrate, copper (Cu) 35 used as an electrode is formed in a front glass substrate 1 (dielectric substrate).
Cu, Ni, and Al all have a very low interfacial coherence with respect to glass. Thus, chromium (Cr) 40 is formed between glass and Cu 35, or between glass and Al 30 or Ni in order to maintain the coupling of the glass and the Cu 35, or that of the glass and the Al 30 or the Ni.
Referring to the forming process, a Cr thin film 40 is formed on the front glass substrate 1 of the PDP by means of a sputtering method in order to heighten the interfacial coherence. Then a Cu film (35) used as an electrode is formed on the Cr thin film 40. Next, another Cr thin film 40 is formed on the Cu film 35 using the sputtering method in order to heighten the interfacial coherence. Finally, employing annealing, a glass is made to cover the entire surface of the front glass substrate 1 inclusive of the Cu film 35 and the Cr thin films 40.
Like the glass substrate, a dielectric substrate is applied to the same manner as the glass substrate. In the same manner, there is formed the electrode on the front glass substrate 11 shown in FIG. 2a.
A conventional electrode of a PDP and a forming method thereof have the following disadvantages.
Since Cr is a pure metal, Cr has a poor interfacial coherence with respect to glass. Besides, in case glass is annealed at a high temperature, interfacial crack or foam is generated at the interface of the glass and the Cr due to their different expansions, and thus the discharge of the PDP becomes unstable and the life span of the PDP becomes shortened. Moreover, since the coupling is made by two metals that are Cu and Cr, that is, an electrode and an interfacial adhesives, sputtering process is carried out for the Cu and another sputtering process is also carried out for the Cr. Accordingly, the overall process is complicated.